A group of horseback riders was slowly advancing along a mountain road, which was slightly foggy.

The group, which was so silent that it seemed to blend in with the scenery due to the hiding, moved forward silently, and all of them were on the lookout for the surroundings. From their appearance and swarthy atmosphere, if a normal person had seen them, he or she would have known that they were not on a sightseeing trip, even though it was obvious that they were not a respectable person.

In fact, there was no time for that. At least, not until the mission is accomplished.

"...Finally."

Among the group, I finally muttered after a long silence. After passing through a dense thick forest, we came to an abandoned village. A quiet, abandoned village with no sign of life at all...

"......"

In silence, I turn my eyes to the map. This deserted village is one of the dozens of villages and three cities that form a county named Kohanami county in Kashu province, Fuso-kuni's northern region. According to the family register maintained by the county office, it has a population of 152. However, from the looks of it, it seems that not a single person lives there anymore.

"One group will stay here. The other team will split into two and search every house in the village. But do not enter the houses of the village headman, the sake brewer, or the village doctor. Makura, you're with the search team. If you don't, we won't be able to divide equally."

I dismounted my horse, turned around, and ordered. I brought two groups of ten people, seven on horseback and three in two-horse carriages. The wagons also carry food and other supplies for this mission. Since one group cannot be divided equally, we have no choice but to bring one person from each of the remaining groups. Even though I wanted a group of three for precaution and support.

"The rest of you stay here. Take care of the horses. If you see any danger, get out. Ignore us. Someone needs to report back."

It had been almost a month and a half since contact with the village had been lost. The letter carriers and merchants who went to the village stopped coming back, followed by the officials who went to see the village headman to discuss the collection of tribute. The county governor wondered why and sent ten soldiers from his army to check on the situation. Then came a request to the Kizuki family.

"As for Yun-shoku-dono?"

"I'll go to the three houses I mentioned. That's the division of labor. Just be careful."

I ordered my men to be careful, and I picked up my spear and headed for the village. My first stop is the village doctor's house. There were blood stains on the walls. They belonged to more than one person and were probably the result of some kind of medical treatment. However, neither the living nor the dead were found. There were scratches on the doorway. The claw marks extend from the inside of the clinic to the outside of the door. Scars made by people who were dragged out, trying desperately to resist even though their fingernails were chipped...

"...It's a miss, huh?"

I muttered to myself, and next, I went to the village headman's house. The search for the house, the biggest one in the village, was not far, but not as big as the Kizuki's house, and the search was over soon. I guessed that it was just before dinner. There was a table in the living room. There were seven, one more than the village head's family, which was supposed to be six according to the information. The food was rotten and bug-infested as if it had not yet been eaten.

The last target was a sake brewery. This house, which seems to have been a powerful man in the village along with the village headman, was also very luxurious.

"......"

As soon as I entered the house, I had a bad feeling. Perhaps it was some kind of sixth sense I had picked up from my previous experiences. I took out a matagama from my pocket and wrapped it around my arm. I walk toward the back of the room, trying to keep my footsteps silent.

"No, it's wrong..."

The presence I had sensed was nothing more than a trace. The presence is not in the living space of the sake brewery. But the possibilities are more limited than they were. If that were the case, the owner must have been well aware of the danger. And they could not have anticipated this situation. Then the possible options are...

Step into the brewery next to the house. But at the same time, I feel a noxious air that is far worse than in the house... I cover my nostrils with my arm. I frown. And then, I see it in my vision.

"That's...."

My eyes land on the p;d book lying on the floor of the brewery, and I stop. I stop and crouch down. I put my hand on the book. The book in my hand gives me a bad feeling. It was an evil spirit. It was a negative force. A curse.

"......"

I've been doing this for years. I have a hunch. It's a... well, if one thinks of a horror story or a monster panic story, it's a very predictable one. If I listen carefully, I can hear that onomatopoeia from above my head. Yeah, it's pretty much expected. This is about as common as it gets. I've had plenty of similar experiences. That's why I used Matagama to remove my presence from sight. Judging from the fact that it doesn't jump at me right now from above, I made the right choice. The monster isn't sure I'm there either. It is confused. Well, since its eyeballs are human implants, they can be fooled quite well by Matagami. I did the calculations. Now I just need to figure out how to counter this trap. So?

"Be prepared for this...!!!"

The next thing, I duck my head and swing my right hand. At the same time, there's an indescribable scream and a spray of blood. I leap behind and the whole monster appears in my field of vision.

Sure enough, the thing that falls from the ceiling is clearly not a person. Its whole body is covered with white clothes that hide it down to its feet, and its head is also hidden by black hair that extends down to its feet. Its arms did not appear to be present. Its face, though hidden by its hair, appeared to be wounded, and blood was trickling down its face.

"Okay, its eyes are crushed...!"

I had a hunch from the description of this mission when I accepted it, and I was right. The visuals were the same, and the method was the same, so it was pretty obvious. To be honest, I wanted to kill this monster with a single blow, but I can't afford to be extravagant. The fact that I was able to neutralize the most troublesome mystic's eye with the first blow is a great achievement...!

'Aaaaaaaaaaaaa!"'

"Shut up!!?"

The creature roars in anger, but I don't have to deal with it, so the next moment I throw a spear mercilessly at its abdomen. The spear, fired with the muscles strengthened by spiritual power, skewers the creature's belly and pierces the wall behind it.

'Aaaa... aaa....!!!?'

The skewered and pinned creature struggles desperately, but the spear does not come out. Meanwhile, I close in and swing it again. I wielded the infinitely transparent, 'spider thread' like a whip.

'Aaa... Ggra...!!!?'

With a squelching sound, the creature's head is severed. It spasmed and jerked, but then went limp... I turned the pulley wrapped around my arm to retrieve the spider thread.

"D*mn, this is a pain in the ass..."

I mutter as I turn the pulley and collect the spider thread.

I thought about the possibility of reusing the sharp spider silk that I had collected in the cave before and came up with the idea of attaching a yo-yo-like gadget to the end of the spider thread and wrapping the spider thread itself around the pulley. The yo-yo is then sent to the opponent and swung as it is, so that it can be used like a whip. In addition, since this method may cause amputation of my fingers or arms even if I do not handle it properly, I have to put on a pair of gloves which are made by re-knitting the spider silk after unraveling it.

"Well, although it is dangerous to handle, it is very effective..."

The gloves have been used several times in actual combat as prototypes, and their results are beyond reproach. It is a thread that calamity youkai have concocted as a trap. It can cut off a medium youkai without fail. Even if it is a great youkai, it is guaranteed to cut through the outer skin and inflict a reasonable wound. Although it is dangerous that the range is short and it must be close to the target... it is still better than piercing it with the dagger (tantō). In the worst case, it is possible to cut off the spider threads and leave without retrieving them.

"...Though, I don't want to throw them away because of the limited stock...!"

'Aaaa....!!!?'

At the same time, I turned around and threw the dagger (tantō) at it. At the same time, it reached inside the head of the creature, which was still suspended in the air and trying to attack me even though it was severed, smashing its skull. The creature's mouth opened as if it was about to split open, and its sharp tongue lashed out at my face, but I deflected it away. In exchange, it took away my mask, which I had prepared. That's why I don't feel safe until I crush its head.

"But then, I still don't feel safe, so here's what I'm going to do."

I grab the head, which is still moaning and struggling and flailing around on the floor, its hair flailing around like tentacles, and drag it around, even though its face is pierced by a dagger (tantō). Then, when I found a sake barrel filled with sake, I pulled out the dagger (tantō) and slammed its head into the barrel. The head of the creature is about to scream and sake is pouring into its mouth.

"Here, you can have this one too."

As a final touch, I pour in the entire contents of the bag of salt, which was also on the table. The monster screams like a madman while drowning in the barrel. Seriously, this monster is still in high spirits even though it has been decapitated and has a dagger stuck in its head.

"Hey, don't come out! Sink, sink."

As it tries to get out of the barrel, I hold its head down and cut its hair on the edge of the barrel with a dagger (tantō). This scene looks like I'm trying to drown a man... but it's not a murder case, rather, it's a youkai case.

For the record, both sake and salt seem to have a certain purifying power in this world, as the legends of previous lives say, and therefore their demand is high in this world as well. And, for youkai, it might have been like being thrown into a pool of hydrochloric acid to be poured into a sake barrel filled with salt until it was saturated. For a young youkai, this might kill them. Though it is obviously uneconomical considering the price of salt and booze.

Anyway, the sound of a desperate cry echoes through the room. I mercilessly drown the creature at the bottom of the barrel. There is no use being nice to youkai. I stab it several times with my dagger (tantō) in response to its noise. In no time at all, the clear sake in the barrel turns red and cloudy.

After a while, it becomes quiet, so I let it sink to the bottom of the barrel for a while, and when I think it stops breathing, I put the lid on the barrel with its head still sunk in it. It's my treat, don't hold back, okay?

"Well, just for show... it was a real close call."

I sigh as I pick up the fallen Hannya mask. I knew about its characteristics and hidden weapons, but I still couldn't be too careless. If I had not been so careful, the blow from its tongue would have shattered my head into a thousand pieces. This world is not easy even with prior knowledge.

"Well, well, I guess I have a pretty good idea of what to expect..."

I put on the mask and look around for it. Then my attention is drawn to the sake barrel in the corner of my vision. Considering that the youkai curse book was here, the truth of the matter is obvious. I opened the lid of the barrel. At the same time, a swarm of flies, and the smell of rottenness that makes me want to vomit come out. It must have been two weeks...

"...It's like they say, 'When you curse someone, dig two graves.' (when you wish harm upon someone, you may end up causing harm to yourself as well)"

This guy must have used it on a whim and lost control of it. No, it was designed to be uncontrollable. It is a piece of evil intention, after all, and the maker is rotten to the core. In that sense, this guy is also a victim... No, I can't really defend this guy when they try to use youkai.

"Yun-shoku!? What's going on!!? What was that sound...!?"

Several servants entered the brewery at the sound of the creature's screams. At the same time, they were shaken up when they saw the headless monster skewered on the wall. I smiled at their behavior, put the Matagama in my pocket, and commanded them to leave the room.

"I found the book in question. We need to dispose of the contents and seal the book. Bring the tools from the wagon of the waiting party."

"Huh!? Y-yes, sir!! Understood!"

My voice suddenly rings out and they turn to look at me. They look at each other, slightly puzzled, and then follow my order. They must have been tilting their heads inwardly, as they could not have seen me until just before thanks to the Matagama.

"...Well, let's clean up the mess."

I mutter to myself as I look at the skewered torso of the monster.

First of all, the head and body of the monster's corpse must be burned after taking a specimen, and the book must be sealed up with charms all over it. Next, to search for survivors, to check for other youkai, and to write a report... There was still a lot of work to be done, huh?

* * *

After finishing the mission and the clean-up, I ordered all the members to leave. The village was deserted... and probably all of them had been eaten... However, I found a few young youkai and small youkai caught in the smell of blood, so I exterminated them, washing away any kind of bloodstains. After that, we made a temporary boundary against evil. The real work will be done by the neighboring soldiers who will come later. All we had to do was to report to our client, the governor, and the Kizuki family about what had happened.

"But it ended sooner than I expected. I thought it would be a bit more troublesome if a whole village had been eaten up and the investigators had disappeared..."

Yahagi, who was the leader of one of the two teams that I had brought with me, and who had been assigned as my acting commander in case something should happen to me, opened his mouth. He pulled his horse close to my side as we rode along the mountain path.

"Yes, indeed. We're lucky there was no damage. I hope nothing happened on the way home. The trip is not over until we get home. Don't let your guard down until the end."

In fact, I had experienced being attacked by bandits and youkai on the way home because I had been careless. And indeed, I was more worried about it than about the mission.

...After all, I had a good chance to win the case of this "youkai cursed book." In fact, this "youkai cursed book" itself was similar to one of the sub-events in a game that was originally modeled on this world.

The same kind of thing. Therefore, I was prepared. I was ready.

A cursed book... a book of youkai modified to be used by famous exorcists was once created, and requests for its retrieval were received at certain times in the main story due to its danger and concerns about misuse. Players are free to accept the request, but this event is, as a matter of course, a first-time-killer.

The first eye that I cut and crushed first when I met the monster before was implanted with a low-grade exorcist's mystic eye, and it was the cause of the first kill. I mean, harassing the main character's head to explode the moment their gazes meet without even being allowed to move to the battle screen.

This, however, is what the well-trained players of 'Firefly of the Dark Night (Yamiyo no Hotaru)' expected. These clever players have examined how to clear this sub-event and have succeeded in discovering one condition. ...And yeah, the production team is crazy for thinking of using the youngest daughter of the Ako family as a sacrificial lamb in the first strike during combat scenes only if she's added to the party. They have some seriously messed-up heads. Of course, Murasaki is not resurrected and is treated as dead.

"That's just a bit of a quirk..."

I blurted out, holding the youkai cursed book covered in charms and wrapped in dozens of chains. Although the opponent is modified and has a killing power at first sight, its rating is only medium youkai, and the girl, Ako, who keeps getting killed by that deterrent will die soon, but her power is real. So, to make the situation better than the original scenario, her death flag should be small. That's why I took this mission and participated in person. ...But then, I have a feeling that she might die by other flags. If anything, she can die in an instant, which is even better than the other variations of her death.

"However, it's a gruesome thing..."

I knew from the information I gathered that the village head and the sake brewery were not on good terms. In fact, youkai cursed books are not something that those villagers can get their hands on. It is something that a rich person would have to pay a lot of money to get. And I was able to identify it because I knew the incidents caused by the youkai cursed book, its characteristics, etc. from the knowledge of the original story. I was convinced that the owner of the sake brewery had bought the "youkai cursed book" from a source behind the scenes.

But I wonder how far he was going to curse... In any case, the villagers and their families were all eaten by the uncontrollable youkai, and the owner of the sake brewery must have fled to the brewery. Youkai are not willing to drink sake. So, he thought that he would not be eaten alive if he was shut up in the brewery. However, he still couldn't get out and he died of starvation. That's a depressing thing to report...

"Speaking of which, it's about time..."

The word "depressing" reminds me of 'that'. Yes, the time of destiny, the time of choice, is really coming soon.

In other words, the original of this world. It is the start of the original 'Firefly of the Dark Night (Yamiyo no Hotaru)'...